Frangible lever connection for shears.



F. C. BIGGERT, in.

FRANGIBLE LEVER BONNECTION FOR SHEARS.

APPucAnoH FILED 'FB.24. l9l6.

1,183,620. Patented May16,1916.

HEETI.

2 SHEETS-S WITNESSES mvETbR F. C. BIGGERT, JR. FRANGIBLE LEVER CONNECTION FOR SHEARS.

APPLlCATION FILED FEB. 24, 1916.

Patented May 16, 1916.

2 SHEETSS-HEET 2.

INVENTOR WITNESSES doq/ pin.

trD STATES,

'r rare.

FLORENCE C. BIGGERT, JR., O 'F GRAFTON, PENNSYLVANIA, ASSIGNOR TO UNITED ENGINEERING- & FOUNDRY COMPANY, OF PITTSBURGH, PENNSYLVANIA, A

CORPORATION OF PENNSYLVANIA.

FRANGIBLE LEVER CONNECTION FOR SHEARS.

Specification of Letters Patent.

Patented May 16, 1916.

Application filed February 24, 1916. Serial No. 80,179.

To all whom it may concern:

Be it known that I, FLORENCE C. BIGGERT, Jr., a citizen of the United States, residing at Grafton, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Frangible Lever Connections for Shears, of which the follow ing is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a side elevation of a shear machine embodying my invention. Fig. 2 is a side view, partly in section, showing the lever aw of the shear and its actuating connection. Fig. 3 is a plan view of the jaw. Fig. 4 is a sectional view of the breakable Fig. 5 is a section on the line VV of Fig. 4, and Fig. 6 is a section on the line VIVI of Fig. 2.

My invention has relation to shears, and more particularly to shears of the lever type.

The invention is designed to provide means of simple and efit'ective character for protecting the machine against overloads.

The invention consists in providing a lever jaw with a breakable member which will constitute the weakest part of the shear structure and will give way under excessive pressure.

My invention provides a pin of a character adapted to break along certain definite lines, leaving the broken parts in such condition that no injury can result to the machine therefrom. Heretofore, breakage of one of the pins usually occurred upon an oblique line so that the ends of the broken portions were of a character to exert a powerful wedging and camming action upon each other, which would produce further injury to the machine. Injuries of this character are prevented by my invention.

My invention further consists in providing the driving connection, or pitman for the lever jaw, with means whereby it can become disengaged from operating connection with the aw in case of breakage of the pin connection, but will still be prevented from interfering with other parts of the shear. Heretofore in cases of such breakage the pitman has been. free to become disengaged with the lever jaw; and when so disengaged, with the crank shaft of the ma chine to which it is attached running at high velocity, damage has frequently resulted before the machine could be stopped.

Referring to the accompanying drawings, the numeral 2 designates the frame of the machine, 3 the fixed jaw, 4 the lever jaw having the shear blade 5, 6 the crank shaft and 7 the gearing for driving said shaft. These parts, may be in general, of any usual character and need not be described in detail, being well known in the art. 7

8 designates the pitman which is connect ed with the crank 9 to the crank shaft 6, which extends up within an opening 10 in the rear end of the lever jaw 4, to which it is connected by the breakage pin 11. In accordance with my invention, this pin is preferably made hollow and is further weakened so as to break along certain definite lines. This may be accomplished in various ways, a preferable construction being shown in Figs. 4, 5 and 6. In this construction the pin is weakened by the external grooves 12 and the registering internal grooves 13, leaving between these grooves the relatively thin annular wall 14 of solid metal. The two sets of grooves are preferably separated from each other by a distance equal to the thickness of the pitman 8. When the machine is subjected to an overload, the pin 11 will fracture at its two weakened portions, thus preventing injury to other parts of the machine. The fractures will be clean, clearcut fractures, leaving no wedging or cammed ends on the broken portions which can cause further injury before the machine is stopped. The pins are designed to be removably seated so as to be easily renewed when broken. They may be secured in place by a pin 15 extending through one end portion thereof, or in any other suitable manner. In order to prevent the pitman from being disengaged from the aw 4 when the pin 11 breaks, I provide it with an upward steeple projection 16 of sufficient length to prevent the pitman fro-m being thrown out of the openin 10 in any position of the crank 9. This efiectually prevents threshing around of the pitman which is likely to cause injury when it occurs.

My invention adds but little, if anything,

to the cost of the-shear and its operationi prevents the possibilityof serious'damages to the machine which might otherwise occur. I

I claim: 1; In a lever shear, a lever j aw having. an

actuating member connected thereto, the

connection between said member and the jaw comprising a breakable-pin having-definite weakened fracture points; substantially as described.

2. In a lever shear, a lever jaw having an actuating member connected thereto, the connection between said member and the jaw comprising a breakable pin, said pinha'ving 3 two separate weakened-portions adapted to causefra'cture of the pin on' lines at sub stantially right angles to the axis thereof; substantially as described.

3. In a' lever shear, a lever j aw" having an actuatmg member connected thereto, the

connection between said memb'eFa-nd' the jaw comprlslnga breakable pin, saldpln be ing hollow and 'havlng separate sets ofwea'kening grooves or cuts adapted to cause me:

ture on lines at substantially right angles to the axis. o'fi the pin}. substantially) as described.

4..In a lever shear, the combination with y a; lever aw' having;afifopeningtlleretlirough, 

